Controller shenanigans

main.js

const HID = require('node-hid')
const Bitfield = require("bitfield")
const SimpleADB = require('simple-adb').SimpleADB;
require('log-timestamp')

const sadb = new SimpleADB();
const devices = HID.devices()
const device = new HID.HID(devices[0].path)
const names = ['zr','zl','r','l','x','a','b','y','null','null','record','home','cr','cl','plus','minus']
const keymap = {
  up: 19,
  down: 20,
  left: 21,
  right: 22,
  home: 3,
  record: 26,
  plus: 82,
  a:66,
  x:52,
  y:53,
  b:4
}
let controller = []
let readable = { }
function update_button(key, state) {
  if((readable[key] == null) || (readable[key].state !== state)) {
    readable[key] = {
      time: Date.now(),
      state: state
    }
    console.log('state change on '+key+': '+(state?'true':'false'))
    if(state) [
      sadb.execAdbShellCommand(['input','keyevent',keymap[key]])
    ]
  }
}
function btn_update() {
  for(i = 0; i < names.length; i++) {
    update_button(names[i], controller[i])
  }
  if(controller[20]) {
    update_button('up',false)
    update_button('down',false)
    update_button('right',false)
    update_button('left',false)
  } else {
    const dpad = (controller[21]?1:0) + (controller[22]?2:0) + (controller[23]?4:0)
    switch(dpad) {
      case 0:
        update_button('up',true)
        update_button('down',false)
        update_button('right',false)
        update_button('left',false)
        break
      case 1:
        update_button('up',false)
        update_button('down',true)
        update_button('right',false)
        update_button('left',false)
        break
      case 2:
        update_button('up',false)
        update_button('down',false)
        update_button('right',true)
        update_button('left',false)
        break
      case 3:
        update_button('up',false)
        update_button('down',false)
        update_button('right',false)
        update_button('left',true)
        break
      case 4:
        update_button('up',true)
        update_button('down',false)
        update_button('right',true)
        update_button('left',false)
        break
      case 5:
        update_button('up',false)
        update_button('down',true)
        update_button('right',false)
        update_button('left',true)
        break
      case 6:
        update_button('up',false)
        update_button('down',true)
        update_button('right',true)
        update_button('left',false)
        break
      case 7:
        update_button('up',true)
        update_button('down',false)
        update_button('right',false)
        update_button('left',true)
        break
    }
  }
}

device.on("data", (data) => {
  const field = Bitfield(data)
  for (i = data.length*8; i >= 0; i--) {
    let got = field.get(i)
    if (controller[i] != got) {
      controller[i] = got
    }
  }
  btn_update()
})